Ace comedian, Jim Carrey is back as a career-obsessed lawyer and divorced father Fletcher Reede. His son Max lives with his ex-wife Audrey. Poor Max longs to spend time with his dad, but it seems that Fletcher is just too busy and forgetful to fulfill his son's wish. When Fletcher misses Max’s fifth birthday, Max takes drastic measures and wishes that his father could refrain from lying for one entire day. His birthday wish comes true and causes a 24-hour long nightmare for his father.